Lap-chine boat construction



June 28, 1960 R. N. THOMPSQN 2,942,282

LAP-CHINE BOAT CONSTRUCTION Filed Nov. 14. 1955 2 Sheets-Sheet 1 IN V ENTOR.

Rob/55 1 N. TB oM soN Attomvsy June 28, 1960 R. N. THOMPSON 2,942,282

LAP-CHINE BOAT CONSTRUCTION Filed Nov. 14, 1955 2 Sheets-Sheet 2INVENTOR. RObERt .N. Thompson A EtcANE United States Patent LAP-CHINEBOAT CONSTRUCTION Robert Nelson Thompson, Cortland, N.Y., assignor toThompson Boat Company of New York, Inc., Cortland, N.Y., a corporationof New York Filed Nov. 14, 1955, Ser. No. 546,542

1 Claim. (Cl. 9-6) This invention relates to a method of boat hullconstruction, and in particular to a novel means of covering the frameof a boat.

Heretofore, it was necessary to sheathe the skeleton of a boat with aseries of beveled lap-planks of substantially equal width varying thedegree of the angle of the bevel on the lap-planks to conform to thecurve of the boat from bow to stern and also the curve of the bilgesection. First, a method for producing beveled'strakes which formed atight, waterproof fit had to be applied. This is a very detailed methodrequiring skilled labor, good fitting of all faying surfaces, and timeconsuming planning. The fact, that the curve of each strake varies toconform to the sweep of the hull, presents difficulties in the presentmethod. A great number of properly cut and shaped strakes had to be usedin a lap-strake hull, including planks for the garboard, bottom, topsideand sheer. It was then found necessary to place 'hese strakes in aseries of overlapping planks in a lateral position conforming to thecompound curvature of the boat. This method of covering a boat is a verydifficult one. and tedious in comparison to the method brought forth inmy invention.

This invention has, for one of its objects, the facility of covering theframe of a boat using an easier method, reducing the task of bevelingplanks in order to entirely cover the frame.

Another purpose of this invention is to provide a means of sheathing aboat which may be easily adapted for use with respect to the type ofbilge section used, and which also readily conforms to the size andshape of the frame of the boat.

Still another object of the invention is to reduce the necessity ofbeveling a large number of planks in varied degrees in order to fit thecompound curved structure of the frame. This method also reduces thenumber of fastenings used.

With this novel method of construction, it is also possible to employother materials, such as sheet or molded plastic, glass fibers, or sheetor molded aluminum in covering the frame of a boat due to the design andmanner in which the boat is covered.

The present invention also assures a safer means of covering the frameof a boat, lessening the danger of leakage apt to be found in thepresent construction of lapplanked boats.

This invention reduces the time and effort spent in the construction oflap-planked boats and insures correct and exact fit of the seams.

According to the present invention, a fiat sheet of plywood is placedparallel to the skeleton of the boat touching the frame, perpendicularfrom beneath the hand rail, reaching the location of the spray rail, orbetter known as the chine section. The lower edge of this sheet ofplywood encases the lap-chine construction (narrow sheets of plywoodstrakes placed and coupled angularly to conform to the bilge section ofthe boat). This lap-chine construction is held fast and in place bymeans of screws and nuts, or as an alternative, suitable means such asrivets, wood screws, or nails, and reinforced by a spray rail. A secondsheet of plywood is placed at the bottom of the boat running the entiredistance of the keel and thwartship from keel to chine. The outer edgeof this plywood sheet which meets the chine section is placed angularlyto fit into the space constructed, joining the plywood lap-chineconstruction of the bilge section of the boat.

Other objects and advantages of this invention will be fully set forthin the following description and the novel features thereof will bespecifically defined by the appended claim.

Further references are made to the accompanying drawings in which:

' Figure 1 is a cross sectional view of a boat designating lap-chineconstruction.

Figure 2 is a section taken substantially on line 2- -2 of Figure 3 ofthe lap-chine construction at the bilge section.

Figure 3 is a side elevational view, in perspective, of a completed boatshowing the results of the lap-chine construction method.

In Figure l, a typical cross section of the boat, flat sheets ofplywood, light-weight and so grained as to bend and twist readily inconformity with the boats sweeping curve, yet strong enough to takefastenings and hold them without splitting, curling or warping, areused.

One fiat sheet 2 of this type plywood is fastened between the keel 1 andthe turn of the bilge, or chine 12. In this manner the entire bottom ofthe boat length is covered with this flat sheet 2 of plywood, runningfrom the edge of the transom (not shown) to the stem (not shown) of theboat. The plywood 2 also extends thwartship from the keel 1 to the chine12, and is fastened to the flooring ribs 8 by suitable means hereillustrated as machine screws 13 and nuts 14, eliminating the need forseparate bottom planking. The fact that the plywood 2 is of such pliablenature, makes it possible to cover one half of the bottom longitudinalsection of the boat with a single sheet 2 of plywood. In a boatconstruction, where it is desired to use a single sheet for the bottom,this plywood sheet 2 could cover the entire bottom.

Along the bilge section 15 of the boat, a lap-chine construction 16 isintroduced, covering the area of the boat known as the chine 12. Forexample, as shown in Figure 1, three narrow sheets 4 of beveled plywoodstrakes 4 are fastened angularly by means of machine screws 6 and nuts7. The overlap 20 of these strakes 4 are so beveled as to produceperfect overlaying of the strakes 4 and to insure leakproof seams atthis section. The strakes are suitably chamfered on their inboard edgeto cooperate with the adjacent surfaces of the ribs 8. A special marinesealer (not shown) is used to further insure leakproof seams. The sizeof these lap-chine strakes 4 are dependent upon the type of bilgesection 15 used on the boat. The finished surface of this lap-chineconstruction 16 is a compact series of overlapping strakes 4 that aresuccessfully screw fastened to one another; the definite amount ofoverlap 20 is pre-determined.

Another pair of fiat sheets 3 of this same type plywood are placed alongthe topside 22 of the boat, adjoining the ribs 8 of the boat, from thehand rail 23 down to the chine section 12, running the entire sweep ofthe boat from the stem 24 to the transom 25. These are fastened to theribs 8, stem 24, and transom 25 with machine screws 6 and nuts 7. As analternative means of fastening, rivets, wood screws, or nails may beemployed. The lower edge 26 of sheets 3 overlap the lapchineconstruction '16 sufiiciently to provide a perfect encasing of the boatframe. The plywood sheets 3 are the "ahg'les where t'he plywood sheets 3and 2 meet and overlap the lap-chine construction 16 of the bilge 15.

, 'It'will of course be understood that various modificatem maybern'adejinithe form, details, arrangements and 'iiroportions'oftlieapparatus andin the steps and sequence "er steps of theiiietliod withoutdeparting from the scope of the applicants invention, which, generallystated, consists in a method capable of earryin'g out'the objects aboveset 'forth,stic'h as disclosed and defined in the appended claim.

A boat hull including a stem, 21 k'e'el an'd "a rear transom parallel toa plurality 0i transverse "ribs, a single 'b'e'ridable sheet secured tosaid ribs and to the lower edge of said transom and conforming to theshape there- 6 f, said sh'eet "extending forwardly from said transom andsymmetricallyalong the keel of said 'hull, said sheet extending upwardlyand converging forwardly into the stem of said hull the side edges ofsaid sheet defining a chine semen "on said hull, a plurality ofvertically overlapped strake elements secured to said transom and ribs"ahdm'erg'irigintofsaid stern, longitudinal edges of said bendablesheetand upper edges of said strake elements being chamfered forsealingly engaging the inboard side of an adjacent "element single'b'endabl'e side panel elements on opposite sides of said hull andsecured to said transom and ribs and extending from said transom andmerging into said stem, said side panels including a lower longitudinaledge overlapping the upper chamfered edge of the uppermostst'rake'e'lement and a spray rail extending from said transom to saidstem and overlying the outer surface of said side paiiels opposite "the'chamfered edge of said uppermoststrake element.

References Cited -in the iile'of this patent UNITED STATES PATENT S396,776 Sprague J an. 29, 1889 661,246 Holloway Nov. 6, 1900 1,941,586Snadecki Jan. 2, 1934 2,677,139 Canazzi May 4, 1954 Yates '1-":a 224,FOREIGN PATENTS 345,455 Great Britaih 'Mar. 26, 1931 579,035Great-Britain 1iily'-22, 1946 762,895 Great Britain Dec. 5, 19 56 OTHERREFERENCES I Bo"atbuilding ohapel ej) pi blished by Mo'rton ace. NewYork), -191,'- 5age=47s =reli'ed en.

